United States Patent  [ii] Patent Number: 5,129,994
Ebbing et al.  Date of Patent: Jul. 14, 1992
 METHOD AND APPARATUS TO INHIBIT OBSTRUCTION OF OPTICAL TRANSMISSION THROUGH SEMICONDUCTOR ETCH PROCESS CHAMBER VIEWPORT
 Inventors: Peter F. Ebbing, Los Altos; Kien N.
Chuc; Jack Ford, both of San Jose;
Fred H. Hariz, Fremont; Michael N.
Sugarman, San Francisco, all of
 Assignee: Applied Materials, Inc., Santa Clara, Calif.
 Appl. No.: 690,137
 Filed: Apr. 23,1991
 Int. C1.5 H01L 21/306; B44C 1/22
 U.S. CI 156/643; 156/626;
 Field of Search 156/345, 643, 646, 626;
118/712, 713, 724, 50.1, 620, 641; 204/298.31, 298.32; 134/1; 219/121.4, 121.41, 121.51,
 References Cited
U.S. PATENT DOCUMENTS 4,857,139 8/1989 Tashiro et al 156/643
4,883,560 11/1989 Ishihara 156/626
4,964,940 10/1990 Auvert et al 156/345
5,002,631 3/1991 Giapis et al 156/643
Primary Examiner—William A. Powell
Attorney, Agent, or Firm—John P. Taylor
A method and apparatus are described for inhibiting visual obstruction of the window of a semiconductor etch process chamber by deposition of each byproducts thereon by selectively heating the window surfaces adjacent one edge of the window to thereby form a cool region on the window surfaces adjacent the opposite edge of the window whereby the center of the window will remain substantially clear of such depositions. The apparatus for carrying out the method of the invention comprises a first heat transmitting structure disposed on one surface of an optically transparent window adjacent orie edge, and a second heat transmitting structure disposed on the opposite surface of the optically transparent window adjacent the same edge to thereby provide even heating of both surfaces of the window adjacent the one edge, thereby creating a cooler zone on the window surfaces adjacent the opposite edge of the window.
25 Claims, 6 Drawing Sheets